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E.ON Netz manages the transmission grid in Schleswig-Holstein and Lower Saxony, about a third of Germany, hosting 6,250 MW of Germany's 14,250 MW installed wind-generating capacity at the end of 2003. This report focuses on the operational challenges and costs associated with the intensive use of wind power due to wind's variability and unpredictability. Excerpts of the report are provided below. The full report can be accessed at the document links on this page.
E.ON Netz manages the transmission grid in Schleswig-Holstein and Lower Saxony, about a third of Germany, hosting 6,250 MW of Germany's 14,250 MW installed wind-generating capacity at the end of 2003. This report focuses on the operational challenges and costs associated with the intensive use of wind power due to wind's variability and unpredictability. Excerpts of the report are provided below. The full report can be accessed at the document links on this page.
Wind Year 2003 – an overview
In 2003, Germany again led the world in wind energy use thanks to the Renewable Energy Act (EEG). At the end of 2003, wind power plants with a total installed capacity of around 14,350 Megawatts (MW) fed German electricity grids. Of this, the greatest proportion at around 6,250 MW was connected in the E.ON control area. For technical reasons, the intensive use of wind power in Germany is associated with significant operational challenges:
• Only limited wind power is available. In order to cover electricity demands, traditional power station capacities must be maintained as so-called "shadow power stations" at a total level of more than 80 % of the installed wind energy capacity, so that the electricity consumption is also covered during economically difficult periods.
• Only limited forecasting is possible for wind power infeed. If the wind power forecast differs from the actual infeed, the transmission system operator must cover the difference by utilising reserve capacity. This requires reserve capacities amounting to 50 – 60 % of the installed wind power capacity.
• Wind power requires a corresponding grid infrastructure. The windy coastal regions of Schleswig- Holstein and Lower Saxony are precisely the places where the grids have now reached their capacity limits through wind power. At present, just under 300 km of new high-voltage and extra-high voltage lines are being planned there in order to create the transmission capacities required for transporting the wind power.
Electricity generation from wind fluctuates greatly
The level of wind power infeed fluctuates greatly depending on the prevailing wind strength. Due to these significant fluctuations, in 2003 the contribution made by wind power production to cover the respective peak load in the E.ON territory varied between zero in real terms and just under one third of the grid load (FIGURE 2).
Looked at over the course of the year, as the annual wind infeed curve shows (FIGURE 3), the availability of the installed wind power plants was relatively low:
• Simultaneous wind power infeed was maximum 4,980 MW, equivalent to just under 80 % of the installed capacity.
• The average fed-in capacity was less than one sixth of the wind power capacity installed in the yearly average.
• Over half the year, the wind power fed-in was less than 11% of the wind power capacity installed in the yearly average.
